g8lover

Hi,

I have a Pontiac G8Gt with a built 4L80 that supposed should hold above where I am at but I already blew 3 of them in 2 yrs... 2 right after each other which is weird ...(died on the dyno or around the block after)...

I have about 860rwhp; 4300lb car; 4L80; TCI ez-tcu controller....

The overrun or overdrive sprag keeps going bad... and thinking it may because of my gear shifter and how its run on the dyno.... my shifter only allows P, R, N, and OD,.... no D3 or D2.... due to trying to use my stock shifter....

on the dyno we run it using manual shift from the eztcu but having the gear selector in OD...so its just elec shifting it...

I am fearing that due to being in OD and shifting electronically that its not applying the overrun clutch like it does in D3, D2, etc.... is this a issue?...

could this cause an issue on a mustang dyno?.... just darned confused at whay these rebuilds are dying before I even get the car back.,,, I know they are not going into N or anything like that.... but now the thought is cause its not manuallly shifted in D (D3)... and is in OD... that this could be the issue..

Any ideas?... I am just dying !!!!

Thanks for any thoughts....

Ps.. the trans is built by a very reputable well known company that has great rep... so I am very frustrated and confused... thx!!

g8lover

After talking with my trans guys, they confirmed that this was the issue most likely... need to get shifter to go into D3 to do it correctly.... and also get different controller to have more control.... so think I am going to have them help me with the new controller and program and get a new shifter so it can be done correctly!.. so think I am on a good path now... just wish I knew about this sooner...

tiznodd

iTrader: (4)

Yes, always have the selector in D3 when racing the car around. The overrun clutches don't engage when the selector is in OD and all of the power goes through the OD roller, which gets wiped out.